U.S. patent application number 14/210035 was filed with the patent office on 2014-09-18 for methods and systems for separating olefins.
This patent application is currently assigned to Kellogg Brown & Root LLC. The applicant listed for this patent is Kellogg Brown & Root LLC. Invention is credited to Curtis Eng, Vijender Kumar Verma.
Application Number | 20140275674 14/210035 |
Document ID | / |
Family ID | 51530218 |
Filed Date | 2014-09-18 |
United States Patent
Application |
20140275674 |
Kind Code |
A1 |
Verma; Vijender Kumar ; et
al. |
September 18, 2014 |
METHODS AND SYSTEMS FOR SEPARATING OLEFINS
Abstract
Systems and methods for separating one or more olefins are
provided. In one or more embodiments, the method for separating one
or more olefins can include separating at least a portion of one or
more C.sub.3 and heavier hydrocarbons from a hydrocarbon containing
C.sub.1 to C.sub.20 hydrocarbons to provide a first mixture that
can include methane, ethane, ethylene, and/or acetylene. At least a
portion of the first mixture can be hydrogenated to convert at
least a portion of the acetylene to ethane and ethylene. At least a
portion of the methane can be separated from the hydrogenated
mixture to provide a second mixture that can include ethane and
ethylene. At least a portion of the ethylene can be separated from
the second mixture to provide a first product that can include at
least 95 mol % ethylene and a second product that can include at
least 95 mol % ethane.
Inventors: |
Verma; Vijender Kumar;
(Sugar Land, TX) ; Eng; Curtis; (Sugar Land,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kellogg Brown & Root LLC |
Houston |
TX |
US |
|
|
Assignee: |
Kellogg Brown & Root
LLC
Houston
TX
|
Family ID: |
51530218 |
Appl. No.: |
14/210035 |
Filed: |
March 13, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61783970 |
Mar 14, 2013 |
|
|
|
Current U.S.
Class: |
585/259 ;
422/187 |
Current CPC
Class: |
C07C 7/09 20130101; C10G
45/32 20130101; C07C 7/167 20130101; F25J 2230/30 20130101; C10G
2400/20 20130101; F25J 3/0252 20130101; F25J 3/0233 20130101; F25J
2245/02 20130101; C10G 2300/1088 20130101; F25J 2210/04 20130101;
F25J 2215/62 20130101; F25J 3/0242 20130101; C10G 7/00 20130101;
F25J 2210/12 20130101; F25J 3/0238 20130101; F25J 2205/04 20130101;
Y02P 30/40 20151101; F25J 3/0219 20130101; C07C 7/167 20130101;
C07C 11/04 20130101; C07C 7/09 20130101; C07C 11/04 20130101 |
Class at
Publication: |
585/259 ;
422/187 |
International
Class: |
C07C 5/08 20060101
C07C005/08 |
Claims
1. A method for separating one or more olefins comprising:
separating at least a portion of one or more C.sub.3 and heavier
hydrocarbons from a hydrocarbon comprising C.sub.1 to C.sub.20
hydrocarbons to provide a first hydrocarbon mixture comprising
methane, ethane, ethylene, and acetylene; hydrogenating at least a
portion of the first hydrocarbon mixture to convert at least a
portion of the acetylene to ethane and ethylene; separating at
least a portion of the methane from the hydrogenated mixture to
provide a second hydrocarbon mixture comprising ethane and
ethylene; and separating at least a portion of the ethylene from
the second hydrocarbon mixture to provide a first product
comprising at least 95 mol % ethylene and a second product
comprising at least 95 mol % ethane, wherein the ethylene is
separated from the second hydrocarbon mixture at a pressure of
about 360 kPa to about 4,000 kPa.
2. The method of claim 1, further comprising transferring at least
a portion of the second product to a pyrolysis furnace.
3. The method of claim 1, wherein the one or more C.sub.3 and
heavier hydrocarbons are separated from the hydrocarbon comprising
C.sub.1 to C.sub.20 hydrocarbons at a pressure of about 400 kPa to
about 3,000 kPa.
4. The method of claim 1, wherein the methane is separated from the
hydrogenated mixture at a pressure of about 600 kPa to about 4,200
kPa, and the ethylene is separated from the second hydrocarbon
mixture at a pressure of about 500 kPa to about 2,500 kPa.
5. The method of claim 1, wherein at least a portion of the
hydrocarbon comprising C.sub.1 to C.sub.20 hydrocarbons is produced
by cracking a heavy hydrocarbon containing C.sub.4+ hydrocarbons in
a fluid catalytic cracker, a pyrolytic process, or combination
thereof.
6. The method of claim 1, wherein the one or more C.sub.3 and
heavier hydrocarbons are separated from the hydrocarbon comprising
C.sub.1 to C.sub.20 hydrocarbons at a pressure of about 800 kPa to
about 2,000 kPa, the methane is separated from the hydrogenated
mixture at a pressure of about 900 kPa to about 3,500 kPa, and the
ethylene is separated from the second hydrocarbon mixture at a
pressure of about 500 kPa to about 2,500 kPa.
7. The method of claim 1, wherein the first hydrocarbon mixture is
hydrogenated in the presence of a catalyst.
8. The method of claim 1, wherein the methane concentration in the
hydrocarbon comprising C.sub.1 to C.sub.20 hydrocarbons is less
than 12 mol %.
9. A method for separating one or more olefins comprising:
compressing a fluid comprising one or more C.sub.1-C.sub.20
hydrocarbons, water, one or more acid gases, and hydrogen;
scrubbing at least a portion of the compressed fluid to remove at
least a portion of the one or more acid gases; separating at least
a portion of the water from the compressed fluid to provide a
dehydrated fluid containing less than 0.5 mol % water, wherein the
dehydrated fluid comprises the one or more C.sub.1-C.sub.20
hydrocarbons; separating at least a portion of one or more C.sub.4
and heavier hydrocarbons from the dehydrated fluid to provide a
hydrocarbon comprising one or more C.sub.1-C.sub.3 hydrocarbons;
separating at least a portion of one or more C.sub.3 hydrocarbons
from the hydrocarbon comprising one or more C.sub.1-C.sub.3
hydrocarbons to provide a first hydrocarbon mixture comprising
ethane, ethylene, acetylene, and methane; hydrogenating at least a
portion of the first hydrocarbon mixture to convert at least a
portion of the acetylene to ethane and ethylene; separating at
least a portion of the methane from the hydrogenated mixture to
provide a second hydrocarbon mixture comprising ethane and
ethylene; and separating at least a portion of the ethylene from
the second hydrocarbon mixture to provide a first product
comprising at least 95 mol % ethylene and a second product
comprising at least 95 mol % ethane, wherein the ethylene is
separated from the second hydrocarbon mixture at a pressure of
about 360 kPa to about 4,000 kPa.
10. The method of claim 9, further comprising transferring all or a
portion of the second product to a pyrolysis furnace.
11. The method of claim 9, wherein the fluid has a methane
concentration of less than 15 mol %.
12. The method of claim 9, wherein the fluid has a hydrogen
concentration of less than 15 mol %.
13. The method of claim 9, wherein the one or more C.sub.4 and
heavier hydrocarbons are separated from the dehydrated fluid at a
pressure of about 500 kPa to about 3,500 kPa.
14. The method of claim 9, wherein the one or more C.sub.3
hydrocarbons are separated from the hydrocarbon comprising one or
more C.sub.1-C.sub.3 hydrocarbons at a pressure of about 400 kPa to
about 3,000 kPa.
15. The method of claim 9, wherein at least a portion of the
hydrocarbon comprising one or more C.sub.1-C.sub.3 hydrocarbons is
produced by cracking a heavy hydrocarbon containing
C.sub.4+hydrocarbons in a fluid catalytic cracker, a pyrolytic
process, or a combination thereof.
16. The method of claim 9, wherein the one or more C.sub.3 and
heavier hydrocarbons are separated from the hydrocarbon comprising
C.sub.1 to C.sub.20 hydrocarbons at a pressure of about 800 kPa to
about 2,000 kPa, the methane is separated from the hydrogenated
mixture at a pressure of about 900 kPa to about 3,500 kPa, and the
ethylene is separated from the second hydrocarbon mixture at a
pressure of about 500 kPa to about 2,500 kPa.
17. The method of claim 9, wherein the ethylene is separated from
the second hydrocarbon mixture at a pressure of about 500 kPa to
about 2,500 kPa.
18. A system for producing one or more olefins comprising: one or
more first separators for separating at least a portion of one or
more C.sub.3 and heavier hydrocarbons from a hydrocarbon comprising
C.sub.1 to C.sub.20 hydrocarbons to provide a first hydrocarbon
mixture comprising ethane, ethylene, and acetylene; one or more
hydrogenators for hydrogenating at least a portion of the first
hydrocarbon mixture to convert at least a portion of the acetylene
to ethane and ethylene; one or more second separators for
separating at least a portion of the methane from the hydrogenated
mixture to provide a second hydrocarbon mixture comprising ethane
and ethylene; and one or more third separators for separating at
least a portion of the ethylene from the second hydrocarbon mixture
at a pressure of about 360 kPa to about 4,000 kPa to provide a
first product comprising at least 95 mol % ethylene and a second
product comprising at least 95 mol % ethane.
19. The system of claim 18, further comprising a recycle line for
transferring at least a portion of the second product to a
pyrolysis furnace.
20. The system of claim 18, wherein the methane concentration of
the hydrocarbon comprising C.sub.1 to C.sub.20 hydrocarbons is less
than 12 mol %.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Patent
Application having Ser. No. 61/783,970, filed Mar. 14, 2013, which
is incorporated by reference herein.
BACKGROUND
[0002] 1. Field
[0003] Embodiments described generally relate to systems and
methods for separating olefinic hydrocarbons.
[0004] 2. Description of the Related Art
[0005] Olefins are typically produced by converting a hydrocarbon
feed at a high temperature to provide a hydrocarbon mixture
containing various alkane, alkene, and alkyne hydrocarbons. The
hydrocarbon mixture is then fractionated using a series of
distillation columns, fractionation columns, compressors, and
refrigeration systems to cool, condense, and separate the various
hydrocarbon products. Due to the relatively low boiling points of
low molecular weight hydrocarbons, ethylene and propylene are
frequently employed as refrigerants while separating and
fractionating the hydrocarbon mixture.
[0006] Many olefin production processes provide a hydrocarbon
mixture rich in C.sub.2-C.sub.4 alkanes and alkenes. The C.sub.3
and C.sub.4 hydrocarbons can be separated from the hydrocarbon
mixture, in part, due to the higher boiling points of C.sub.3 and
C.sub.4 hydrocarbons relative to other compounds in the hydrocarbon
mixture. However, the separation of the C.sub.2 hydrocarbons into
relatively pure (e.g., greater than 95 mol %) ethane and ethylene
products requires the use of very low temperature (e.g., about
-50.degree. C. to about -140.degree. C.) vapor-liquid flash and
fractional distillation processes due to the relatively similar
boiling points of ethylene (e.g., about -103.7.degree. C.) and
ethane (e.g., about -88.6.degree. C.). Two or more refrigeration
systems employing low temperature propylene and ethylene
refrigerants are required to separate the methane, hydrogen, and
ethylene from ethane. The need for dual refrigerant, low
temperature, refrigeration systems requires both significant
capital costs and significant operating costs. Further, the low
operating temperatures and high operating pressures require the use
of special metallurgies and equipment construction imposing
additional capital and operating costs.
[0007] There is a need, therefore, for improved methods and systems
for separating ethane and/or ethylene from a hydrocarbon mixture
that in addition to ethane and/or ethylene also includes one or
more additional C.sub.1 to C.sub.20 hydrocarbons.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 depicts an illustrative system for separating
hydrocarbons, according to one or more embodiments described.
[0009] FIG. 2 depicts an illustrative cooling system shown in FIG.
1, according to one or more embodiments described.
DETAILED DESCRIPTION
[0010] Methods and system for separating one or more olefins are
provided. In one or more embodiments, the method for separating one
or more olefins can include separating at least a portion of one or
more C.sub.3 and heavier hydrocarbons from a hydrocarbon containing
C.sub.1 to C.sub.20 hydrocarbons to provide a first hydrocarbon
mixture that can include one or more of methane, ethane, ethylene,
and/or acetylene (ethyne). At least a portion of the first
hydrocarbon mixture can be hydrogenated to convert at least a
portion of the acetylene to ethane and ethylene. At least a portion
of the methane can be separated from the hydrogenated mixture to
provide a second hydrocarbon mixture that can include ethane and
ethylene. At least a portion of the ethylene can be separated from
the second hydrocarbon mixture to provide a first product that can
include at least 95 mol % ethylene and a second product that can
include at least 95 mol % ethane. The ethylene can be separated
from the second hydrocarbon mixture at a pressure of about 360 kPa
to about 4,000 kPa or about 500 kPa to about 2,500 kPa.
[0011] FIG. 1 depicts an illustrative system 100 for separating
hydrocarbons according to one or more embodiments. The system 100
can include one or more compressors (two are shown 105, 130), one
or more scrubbers 110, one or more driers 120, one or more
vapor-liquid separators (five are shown 125, 155, 160, 170, 175),
one or more reactor systems (two are shown 135, 165), and one or
more chilling systems 200. The chilling system 200 can include one
or more coolers or cooling systems (two are shown 140, 145). One or
more hydrocarbons via line 102 can be introduced to the compressor
105 to provide a compressed fluid (e.g., compressed hydrocarbon
fluid having gaseous and/or liquid state) via line 109. The
hydrocarbon in line 102 can include one or more liquid
hydrocarbons, gaseous hydrocarbons, fluidized hydrocarbons, or any
mixture thereof. The hydrocarbon in line 102 can include, but is
not limited to, one or more C.sub.1 to C.sub.20 hydrocarbons. The
C.sub.1 to C.sub.20 hydrocarbons can include, but are not limited
to, one or more alkanes, one or more alkenes, one or more alkynes,
or any mixture thereof. The hydrocarbon in line 102 can also
include one or more acid gases. Illustrative acid gases can
include, but are not limited to, carbon dioxide and/or hydrogen
sulfide. The hydrocarbon in line 102 can also include one or more
sour gases or compounds. Illustrative sour gases or compounds can
include, but are not limited to, hydrogen sulfide and organosulfur
compounds, such as mercaptans. The hydrocarbon in line 102 can
include, but is not limited to, hydrogen, methane, ethane,
ethylene, acetylene, propane, propylene, butane, butane, pentane,
pentene, isomers thereof, or any mixture thereof.
[0012] The hydrocarbon in line 102 can include hydrogen in an
amount of about 0.5 mol %, about 1 mol %, about 2 mol %, about 3
mol %, about 4 mol %, or less than 5 mol % to 5 mol %, less than 10
mol %, less than 15 mol %, or less than 25 mol %. The methane
concentration in the hydrocarbon in line 102 can be about 0.5 mol
%, about 1 mol %, about 2 mol %, about 3 mol %, about 4 mol %, or
less than 5 mol % to 5 mol %, less than 10 mol %, less than 15 mol
%, or less than 25 mol %. The ethane concentration in the
hydrocarbon in line 102 can be about 0.5 mol %, about 1 mol %,
about 2 mol %, about 3 mol %, about 4 mol %, or less than 5 mol %
to 5 mol %, less than 10 mol %, less than 15 mol %, or less than 25
mol %. The ethylene concentration in the hydrocarbon in line 102
can be about 0.5 mol %, about 1 mol %, about 2 mol %, about 3 mol
%, about 4 mol %, or less than 5 mol % to 5 mol %, less than 10 mol
%, less than 15 mol %, or less than 25 mol %. The acetylene
concentration in the hydrocarbon in line 102 can be about 0.1 mol
%, about 0.5 mol %, about 0.75 mol %, about 1 mol %, or less than 2
mol % to 2 mol %, less than 3 mol %, less than 5 mol %, or less
than 10 mol %. The propane concentration in the hydrocarbon in line
102 can be about 0.5 mol %, about 1 mol %, about 2 mol %, about 3
mol %, about 4 mol %, or less than 5 mol % to 5 mol %, less than 10
mol %, less than 15 mol %, or less than 25 mol %. The propylene
concentration in the hydrocarbon in line 102 can be about 0.5 mol
%, about 1 mol %, about 2 mol %, about 3 mol %, about 4 mol %, or
less than 5 mol % to 5 mol %, less than 10 mol %, less than 15 mol
%, or less than 25 mol %. The acid gas concentration in the
hydrocarbon in line 102 can be about 0.01 mol %, about 0.05 mol %,
about 0.1 mol %, about 0.2 mol %, about 0.3 mol %, about 0.4 mol %,
or less than 0.5 mol % to 0.5 mol %, less than 0.7 mol %, less than
1 mol %, less than 1.3 mol %, or less than 1.5 mol %. The sour gas
concentration in the hydrocarbon in line 102 can be about 0.01 mol
%, about 0.05 mol %, about 0.1 mol %, about 0.2 mol %, about 0.3
mol %, about 0.4 mol %, or less than 0.5 mol % to 0.5 mol %, less
than 0.7 mol %, less than 1 mol %, less than 1.3 mol %, or less
than 1.5 mol %.
[0013] The hydrocarbon in line 102 can be at a pressure of about
100 kPa, about 300 kPa, about 500 kPa, or about 700 kPa to about
800 kPa, about 1,000 kPa, about 1,300 kPa, or about 1,500 kPa. The
hydrocarbon in line 102 can be at a temperature of about 0.degree.
C., about 5.degree. C., about 10.degree. C., or about 15.degree. C.
to about 75.degree. C., about 80.degree. C., about 90.degree. C.,
or about 100.degree. C.
[0014] In one or more embodiments, one or more C.sub.4 and heavier
hydrocarbons (e.g., C.sub.4+hydrocarbons) can be cracked or
otherwise processed in a high temperature, pyrolytic process to
produce the hydrocarbon in line 102. In other embodiments, one or
more C.sub.3 and heavier hydrocarbons from a hydrocarbon containing
C.sub.1 to C.sub.20 hydrocarbons can be separated or otherwise
processed to produce the hydrocarbon in line 102. Illustrative
pyrolytic processes can include, but are not limited to, fluid
catalytic cracking ("FCC"), thermal cracking, hydrocracking, or any
combination thereof. An illustrative advanced catalytic olefins
("ACO") process and system suitable for producing at least a
portion of the hydrocarbon in line 102 can include those discussed
and described in U.S. Pat. No. 7,301,063. An illustrative methanol
to olefins ("MTO") process and system, suitable for producing at
least a portion of the hydrocarbon in line 102 can include those
discussed and described in U.S. Pat. Nos. 5,191,141; 4,590,320;
4,550,217; and 4,496,786. As such, at least a portion of the
hydrocarbon in line 102 can be produced by cracking a heavy
hydrocarbon containing C.sub.4+ hydrocarbons in a fluid catalytic
cracker, an advanced catalytic olefins process, a methanol to
olefins process, a thermal cracker, a hydrocracker, or any
combination thereof.
[0015] In one or more embodiments, the hydrocarbon in line 102
produced via one or more pyrolytic processes, such as the FCC, ACO,
and/or MTO process, can have low concentrations of hydrogen and
methane. For example, the hydrocarbon in line 102 can include less
than 15 mol % hydrogen and less than 15 mol % methane. The low
hydrogen and methane concentrations can permit the separation of
the hydrogen and methane from the hydrocarbon at pressures greater
than 1,000 kPa and temperatures greater than the boiling point of
propylene (e.g., about -47.4.degree. C.) to provide an
ethylene/ethane mixture. The reduced concentration of hydrogen and
methane in the ethane/ethylene mixture can permit subsequent
separation of the ethylene/ethane mixture into a relatively pure
ethane product, e.g., greater than 95 mol % ethane, and a
relatively pure ethylene product, e.g., greater than 95 mol %
ethylene, at a pressure of about 360 kPa or greater and a
temperature of about -47.4.degree. C. or greater. The power
required to provide the higher separation pressure, however,
increases the overall energy consumption.
[0016] As depicted in FIG. 1, the compressor 105 can include a
first stage 106 that can provide a first compressed fluid (e.g.,
compressed hydrocarbon fluid having gaseous and/or liquid state)
via line 107 and a second stage 108 that can provide the first
compressed fluid via line 109. In one or more embodiments, the
first stage 106 and the second stage 108 can be separate,
independent compressors. The one or more compressors 105 can
include one or more systems, devices or combination of systems
and/or devices suitable for compressing a fluid at a first pressure
to provide a fluid at a second pressure, where the second pressure
is greater than the first pressure. In one or more embodiments, the
pressure of the compressed fluid in line 102 can be increased by
about 500 kPa or greater, about 1,000 kPa or greater, about 1,500
kPa or greater, or about 2,000 kPa or greater by passage through
the first stage 106 and the second stage 107. The pressure of the
compressed fluid in line 109 can be about 600 kPa, about 1,300 kPa,
about 2,000 kPa, or about 2,700 kPa to about 1,700 kPa, about 2,500
kPa, about 3,000 kPa, about 3,500 kPa, or greater. In one or more
embodiments, the compressor 105 can include one or more stages (two
as shown 106, 108). In one or more embodiments, the compressor 105
can include one or more liquid and/or air cooled intercoolers
between any two or more compressor stages. In one or more
embodiments, shaft power can be supplied to the one or more
compressors 105 via one or more electric motors, steam turbines,
gas turbines, or any combination thereof.
[0017] The compressed fluid in line 109 can be introduced to the
one or more scrubbers 110, where at least a portion of any acid
gases present can be converted to one or more insoluble compounds
and removed from the compressed fluid. A caustic solution can be
introduced or otherwise flowed into the scrubber 110 via line 111.
The caustic solution can have a pH of greater than 7, such as about
8 to about 14, or about 8.5 to about 12. In some example, the
caustic solution can include an aqueous solution or mixture
containing one or more of a hydroxide, a hypochlorite, ammonium, an
amine, or other basic compounds. A spent caustic solution via line
114 can be recovered from the scrubber 110 for treatment,
regeneration, and/or disposal and a scrubbed fluid via line 112 can
be recovered from the scrubber 110. A spent caustic solution via
line 114 can be recovered from the scrubber 110 for treatment,
regeneration, and/or disposal. The operating pressure of the
scrubber 110 can be about 600 kPa, about 1,300 kPa, about 1,700
kPa, about 2,000 kPa, about 2,500 kPa, or about 2,700 kPa to about
3,000 kPa, about 3,500 kPa, or greater. The operating temperature
of the scrubber 110 can be about 0.degree. C., about 5.degree. C.,
about 10.degree. C., or about 15.degree. C. to about 75.degree. C.,
about 80.degree. C., about 90.degree. C., or about 100.degree.
C.
[0018] The scrubber 110 can include one or more systems, devices or
any combination of systems and/or devices suitable for removing all
or a portion of the one or more acid gases in the compressed fluid
in line 109 to provide a low (or reduced) acid concentration
compressed fluid via line 112 and the spent caustic solution via
line 114. The acid concentration in the compressed fluid in line
114 can be about 5 mol % or less, about 3 mol % or less, about 1
mol % or less, about 0.5 mol % or less, about 0.1 mol %, or less.
The scrubber 110 can include one or more recirculation systems for
recirculation of the caustic scrubbing solution through the
scrubber 110. The scrubber 110 can be a vertical column having a
length over diameter (L/D) ratio greater than 1, greater than 5, or
greater than 10. In one or more embodiments, all or a portion of
the interior of the scrubber 110 can be filled with trays and/or
packing to increase the effective mass transfer area within the
scrubber 110. In one or more embodiments, all or a portion of the
interior of the scrubber 110 can be empty, that is without trays or
packing.
[0019] The scrubbed fluid in line 112 can be introduced to the
drier 120, where at least a portion of any water present in the
scrubbed fluid can be removed to provide a recovered water via line
124 and an at least partially dried fluid via line 122. The drier
120 can include one or more deliquescent driers, regenerative
desiccant driers, refrigeration driers, membrane driers, or any
combination thereof. The dried fluid exiting the drier via line 122
can have a dew point of about 0.degree. C. or less, about
-20.degree. C. or less, about -40.degree. C. or less, about
-80.degree. C. or less, about -100.degree. C., or less. The
temperature of the dried fluid in line 122 can be about 500 kPa,
about 1,000 kPa, about 1,400 kPa, or about 1,800 kPa to about 1,700
kPa, about 2,500 kPa, about 3,000 kPa, about 3,500 kPa, or
greater.
[0020] In one or more embodiments, the dried fluid in line 122 can
be introduced to the vapor-liquid separator 125 to provide an
overhead via line 126 and bottoms via line 128. In some
embodiments, the vapor-liquid separator can be a "depropanizer" and
the bottoms via line 128 can include C.sub.4 and heavier
hydrocarbons and the overhead via line 126 can include C.sub.3 and
lighter hydrocarbons. In other embodiments, the vapor-liquid
separate can be a "deethanizer" and the bottoms via line 128 can
include one or more C.sub.3 and heavier hydrocarbons and the
overhead via line 126 can include C.sub.1 and C.sub.2 hydrocarbons.
For simplicity and ease of description, the system 100 will be
further discussed and describe in the context of 125 as a
depropanizer. The operating pressure of the depropanizer 125 can be
about 500 kPa, about 1,000 kPa, about 1,400 kPa, about 1,500 kPa,
or about 1,600 kPa to about 1,700 kPa, about 1,800 kPa, about 2,500
kPa, about 3,000 kPa, about 3,500 kPa, or greater. The operating
temperature of the depropanizer 125 can be about -73.degree. C.,
about -65.degree. C., about -60.degree. C., about -55.degree. C.,
about -53.degree. C., about -50.degree. C., about -48.degree. C.,
about -45.degree. C., about -43.degree. C., about -40.degree. C.,
about -38.degree. C., about -35.degree. C., about -33.degree. C.,
about -30.degree. C., about -27.degree. C., about -25.degree. C.,
or about -23.degree. C. to about -20.degree. C., about -17.degree.
C., about -15.degree. C., about -13.degree. C., about -10.degree.
C., about -8.degree. C., about -5.degree. C., about -3.degree. C.,
about 0.degree. C., about 5.degree. C., about 10.degree. C., about
12.degree. C., about 15.degree. C., or about 17.degree. C.
[0021] In some embodiments, the C.sub.4 and heavier hydrocarbons
via line 128 can include, but are not limited to, butane, butene,
butylene, pentane, pentene, isomers thereof, unsaturated
derivatives thereof, or any mixture thereof. In an alternative
embodiment, the C.sub.3 and heavier hydrocarbons via line 128 can
include, but are not limited to, propane, propylene, butane,
butene, butylene, pentane, pentene, isomers thereof, unsaturated
derivatives thereof, or any mixture thereof. In one or more
embodiments, all or a portion of the C.sub.3 and heavier
hydrocarbons or the C.sub.4 and heavier hydrocarbons in line 128
can be recycled to a pyrolytic or other process used to produce at
least a portion of the hydrocarbon in line 102. The pressure of the
C.sub.3 and heavier hydrocarbons or the C.sub.4 and heavier
hydrocarbons in line 128 can be about 300 kPa, about 500 kPa, about
600 kPa, or about 700 kPa to about 1,700 kPa, about 2,100 kPa,
about 2,500 kPa, about 3,000 kPa, or greater. The temperature of
the C.sub.3 and heavier hydrocarbons or the C.sub.4 and heavier
hydrocarbons in line 128 can be about -60.degree. C., about
-50.degree. C., or about -40.degree. C., to about 0.degree. C.,
about 10.degree. C., about 20.degree. C., or about 30.degree.
C.
[0022] In one or more embodiments, the depropanizer 125 can include
one or more systems, devices, or any combination of systems and/or
devices suitable for selectively separating C.sub.3 and lighter
hydrocarbons from a mixture containing one or more C.sub.1 to
C.sub.20 hydrocarbons. The depropanizer 125 can be a vertical
column having a length over diameter (L/D) ratio greater than 1,
greater than 5, or greater than 10 in some embodiments. All or a
portion of the interior of the depropanizer 125 can be filled with
trays and/or packing to increase the effective mass transfer area
within the depropanizer 125. All or a portion of the interior of
the depropanizer 125 can be empty, that is without trays or
packing. One or more condensers can be located internal or external
to the depropanizer 125. One or more reboilers can be located
internal or external to the depropanizer 125.
[0023] The overhead in line 126 can include, but is not limited to,
hydrogen, methane, ethane, ethylene, acetylene, propane, propylene,
isomers thereof, or any mixture thereof. The hydrogen concentration
in the overhead in line 126 can be about 0.1 mol %, about 0.5 mol
%, about 1 mol %, or about 2 mol % to less than 5 mol %, less than
7 mol %, less than 10 mol %, or less than 15 mol %. The methane
concentration in the overhead in line 126 can be about 0.1 mol % to
less than 12 mol %, such as about 0.1 mol %, about 0.5 mol %, about
1 mol %, or about 2 mol % to about 3 mol %, about 5 mol %, about 7
mol %, or less than 12 mol %. The ethane concentration in the
overhead in line 126 can be can be about 0.5 mol %, about 1 mol %,
about 2 mol %, about 3 mol %, about 4 mol %, or less than 5 mol %
to 5 mol %, less than 10 mol %, less than 15 mol %, or less than 25
mol %. The ethylene concentration in the overhead in line 126 can
be about 0.5 mol %, about 1 mol %, about 2 mol %, about 3 mol %,
about 4 mol %, or less than 5 mol % to 5 mol %, less than 10 mol %,
less than 15 mol %, or less than 25 mol %. The acetylene
concentration in the overhead in line 126 can be about 0.1 mol %,
about 0.5 mol %, about 0.75 mol %, about 1 mol %, about 1.3 mol %,
about 1.5 mol %, or about 2 mol % to about 2.5 mol %, about 3 mol
%, less than 5 mol %, less than 7 mol %, or less than 10 mol %. The
propane concentration in the overhead in line 126 can be about 0.5
mol %, about 1 mol %, about 1.5 mol %, about 2 mol %, about 3 mol
%, about 4 mol %, or about 5 mol % to about 6 mol %, about 8 mol %,
less than 10 mol %, less than 15 mol %, or less than 25 mol %. The
propylene concentration in the overhead in line 126 can be about
0.5 mol %, about 1 mol %, about 2 mol %, about 3 mol %, about 4 mol
%, or less than 5 mol % to 5 mol %, less than 10 mol %, less than
15 mol %, or less than 25 mol %.
[0024] The overhead in line 126 can be at a pressure of about 400
kPa, about 600 kPa, about 800 kPa, or about 900 kPa to about 1,700
kPa, about 2,000 kPa, about 2,500 kPa, or about 3,000 kPa. The
overhead in line 126 can be at a temperature of about -73.degree.
C., about -65.degree. C., about -60.degree. C., about -55.degree.
C., about -53.degree. C., about -50.degree. C., about -48.degree.
C., about -45.degree. C., about -43.degree. C., about -40.degree.
C., about -38.degree. C., about -35.degree. C., about -33.degree.
C., about -30.degree. C., about -27.degree. C., about -25.degree.
C., or about -23.degree. C. to about -20.degree. C., about
-17.degree. C., about -15.degree. C., about -13.degree. C., about
-10.degree. C., about -8.degree. C., about -5.degree. C., about
-3.degree. C., about 0.degree. C., about 5.degree. C., about
10.degree. C., about 12.degree. C., about 15.degree. C., or about
17.degree. C.
[0025] The overhead via line 126 can be introduced to the
compressor 130 to provide a compressed fluid via line 132. The
pressure of the overhead in line 126 can be increased by about
1,500 kPa or greater, about 2,000 kPa or greater, about 2,500 kPa
or greater, or about 3,000 kPa or greater, by passage through the
one or more compressors 130. The compressed fluid in line 132 can
be at a pressure of about 1,900 kPa, about 2,100 kPa, about 2,300
kPa, or about 2,400 kPa to about 4,700 kPa, about 5,000 kPa, about
5,500 kPa, about 6,000 kPa, or greater.
[0026] The compressor 130 can include one or more systems, devices,
or combination of systems and/or devices suitable for compressing a
fluid at a first pressure to provide a fluid at a second pressure,
where the second pressure is greater than the first pressure. The
compressor 130 can include one or more stages, two or more separate
and independent compressors, or a combination thereof. The
compressor 130 can include one or more intercoolers between any two
or more compressors and/or compressor stages. Shaft power can be
supplied to the one or more compressors 130 via one or more
electric motors, steam turbines, gas turbines, or any combination
thereof.
[0027] The compressed fluid via line 132 can be introduced to the
reactor system ("acetylene converter") 135, where at least a
portion of any acetylene present in the compressed fluid can be
converted to ethane and/or ethylene to provide a hydrogenated
mixture via line 136. Hydrogen can be introduced via line 138 to
the compressed fluid in line 132 prior to introducing the
compressed fluid to the acetylene converter 135 or the hydrogen can
be introduced directly to the acetylene converter 135. The hydrogen
introduced via line 138 can be about 50 mol % hydrogen or greater,
about 75 mol % hydrogen or greater, about 90 mol % hydrogen or
greater, about 95 mol % hydrogen or greater, about 99 mol %
hydrogen or greater, or about 99.9 mol % hydrogen or greater. The
hydrogen in 138 can contain carbon monoxide and/or carbon
dioxide.
[0028] In one or more embodiments, about 75%, about 80%, about 90%,
about 95%, about 99%, or about 99.9% of the acetylene present in
the compressed process fluid in line 132 can be converted to ethane
and/or ethylene in the acetylene converters 135. The acetylene
concentration in the hydrogenated mixture via line 136 can be about
1 mol % or less, about 0.5 mol % or less, about 0.1 mol % or less,
about 0.05 mol % or less, about 0.03 mol % or less, about 0.01 mol
%, or less. The pressure of the hydrogenated mixture in line 136
can be about 1,100 kPa, about 1,300 kPa, about 1,400 kPa, or about
1,500 kPa to about 4,200 kPa, about 4,400 kPa, about 4,700 kPa,
about 5,200 kPa, or greater.
[0029] The one or more acetylene converters 135 can include one or
more systems, devices or combination of systems and/or devices
suitable for converting at least a portion of any acetylene present
in the compressed process fluid in line 132 to ethane and ethylene.
The one or more acetylene converters 135 can contain one or more
catalyst beds. The one or more catalyst beds can be fixed beds,
fluidized beds, ebullating beds, slurry beds, moving beds, bubbling
beds, any other suitable type of catalyst bed, or any combination
thereof. The one or more acetylene converters 135 can include one
or more dual-bed converter systems such as those discussed and
described in U.S. Pat. No. 7,038,097. The catalyst within the
acetylene converter 135 can include, but is not limited to, one or
more nickel based catalysts, such as Ni/NiAl.sub.2O.sub.4, one or
more palladium based catalysts, such as Pd/PdAl.sub.2O.sub.3,
alloys thereof, derivatives thereof, combinations thereof, or any
mixture thereof.
[0030] The hydrogenated mixture via line 136 can be introduced to
the chilling system 200 to provide a cooled hydrogenated mixture
via lines 142 and/or 147. The chilling system 200 can include a
first cooler 140 and a second cooler 145. The first cooler 140 can
condense at least a portion of the hydrogenated mixture, which can
be recovered via line 142. Non-condensed hydrogenated mixture can
be recovered via line 144 from the first cooler 140, which can be
introduced to the second cooler 145 to provide a condensed
hydrogenated mixture via line 147 and tail gases via lines 149 and
151. A hydrogen-rich tail gas can be recovered via line 149 and a
hydrogen-lean tail gas can be recovered via line 151. In some
embodiments, the hydrogen-lean tail gas recovered via line 151, or
any other fluid or composition, can be recycled or otherwise flowed
via line 152 (e.g., a bypass line) to the compressor 105, such as
to line 107 disposed downstream of the first stage 106 and upstream
of the second stage 108, as depicted in FIG. 1. Alternatively,
although not show, the hydrogen-lean tail gas or other fluid or
composition via line 152 can be recycled or otherwise flowed
upstream of the first stage 106, such as to line 102 or downstream
of the second stage 108, such as to line 109.
[0031] The first cooler 140 and/or the second cooler 145 can cool
the hydrogenated mixture introduced via line 136 using any suitable
heat transfer medium or combination of heat transfer mediums.
Illustrative heat transfer mediums that can be used to cool the
hydrogenated mixture introduced to the first cooler 140 can
include, but are not limited to, ethylene, propylene, cooling
water, air, any combination thereof, or any mixture thereof.
Illustrative heat transfer mediums that can be used to cool the
non-condensed hydrogenated mixture introduced via line 144 to the
second cooler 145 can include, but are not limited to, propylene.
The first cooler 140, the second cooler 145, or both can use
refrigerated propylene as the heat transfer medium. The use of
refrigerated ethylene to cool the hydrogenated mixture is not
required. In one or more embodiments, refrigerated propylene at a
temperature of about 5.degree. C., about 0.degree. C., about
-5.degree. C., about -10.degree. C., about -20.degree. C., about
-30.degree. C., about -40.degree. C., or less can be used to
indirectly cool the hydrogenated mixture introduced via line 136 to
the chilling system 200.
[0032] The chilling system 200 can include any suitable system,
device, or combination of systems and/or devices for cooling the
hydrogenated mixture in line 136. The chilling system 200 can
include one or more heat exchangers. For example, the chilling
system 200 can include, but is not limited to, one or more
shell-and-tube heat exchangers, core-type heat exchangers, plate
and frame heat exchangers, spiral wound heat exchangers, U-tube
heat exchangers, and/or bayonet style heat exchangers. The one or
more heat exchangers can include surface enhanced tubes (e.g.,
fins, static mixers, rifling, heat conductive packing, turbulence
causing projections, or any combination thereof), and the like.
[0033] In one or more embodiments, at least a portion of the
condensed hydrogenated mixture via line 142 and/or line 147 can be
introduced to the vapor-liquid separator ("demethanizer") 155 to
provide a methane-rich overhead via line and methane-lean bottoms
via line 159. In one or more embodiments, at least a portion of the
condensed hydrogenated mixture in line 142 can be recycled via line
143 to the depropanizer 125 as a reflux. In one or more
embodiments, at least a portion of the condensed hydrogenated
mixture in line 147 can be recycled via line 148 to the compressor
105. As illustrated, a portion of the hydrogenated mixture in line
147 can be recycled via line 148 to the first stage 106 and/or a
portion can be recycled to the second stage 108.
[0034] In one or more embodiments, at least a portion of the
methane-rich overhead via line 157 can be recycled to the
compressor 130. In one or more embodiments, all or a portion of the
methane-rich overhead via line 157 can be recovered as a product,
which can be further processed or used as fuel, for example.
[0035] The operating pressure of the demethanizer 155 can be about
600 kPa, about 700 kPa, about 800 kPa, or about 900 kPa to about
2,500 kPa, about 2,700 kPa, about 2,900 kPa, about 3,500 kPa, about
4,000 kPa, or about 4,200 kPa. The operating temperature of the
demethanizer 155 can be greater than the boiling point of propylene
(e.g., about -48.1.degree. C.). The operating temperature of the
demethanizer 155 can be about -48.degree. C., about -45.degree. C.,
about -43.degree. C., about -40.degree. C., about -38.degree. C.,
about -35.degree. C., about -33.degree. C., about -30.degree. C.,
about -27.degree. C., about -25.degree. C., about -23.degree. C.,
about -20.degree. C., about -17.degree. C., about -15.degree. C.,
or about -13.degree. C. to about -10.degree. C., about -7.degree.
C., about -5.degree. C., about -3.degree. C., about 0.degree. C.,
about 5.degree. C., about 10.degree. C., about 12.degree. C., about
15.degree. C., or about 17.degree. C.
[0036] The demethanizer 155 can include one or more systems,
devices, or any combination of systems and/or devices suitable for
providing the methane-rich overhead via line 157 and the
methane-lean bottoms via line 159. The demethanizer 155 can be a
vertical column having a length over diameter (L/D) ratio greater
than 1, greater than 5, or greater than 10. All or a portion of the
interior of the demethanizer 155 can be filled with trays and/or
packing to increase the effective mass transfer area within the
demethanizer 155. All or a portion of the interior of the
demethanizer 155 can be empty, that is without trays or packing.
One or more condensers can be located internal or external to the
demethanizer 155. One or more reboilers can be located internal or
external to the demethanizer 155.
[0037] The methane-lean bottoms via line 159 can be introduced to
the vapor-liquid separator ("deethanizer") 160 to provide a
C.sub.2-rich overhead via line 161 and a C.sub.2-lean bottoms via
line 163. The operating pressure of the deethanizer 160 can be
about 400 kPa, about 600 kPa, about 800 kPa, about 900 kPa, about
1,000 kPa, about 1,200 kPa, or about 1,400 kPa to about 1,700 kPa,
about 2,000 kPa, about 2,500 kPa, about 3,000 kPa, about 3,500 kPa,
or about 4,000 kPa. The operating temperature of the deethanizer
160 can be about -73.degree. C., about -65.degree. C., about
-60.degree. C., about -55.degree. C., about -53.degree. C., about
-50.degree. C., about -48.degree. C., about -45.degree. C., about
-43.degree. C., about -40.degree. C., about -38.degree. C., about
-35.degree. C., about -33.degree. C., about -30.degree. C., about
-27.degree. C., about -25.degree. C., or about -23.degree. C. to
about -20.degree. C., about -17.degree. C., about -15.degree. C.,
about -13.degree. C., about -10.degree. C., about -8.degree. C.,
about -5.degree. C., about -3.degree. C., about 0.degree. C., about
5.degree. C., about 10.degree. C., about 12.degree. C., about
15.degree. C., or about 17.degree. C.
[0038] The ethane concentration in the C.sub.2-rich overhead in
line 161 can be about 3 mol %, about 9 mol %, about 18 mol %, or
about 35 mol % to about 40 mol %, about 47 mol %, about 55 mol %,
about 70 mol %, about 85 mol %, or about 97 mol %. The ethylene
concentration in the C.sub.2-rich overhead in line 161 can be about
3 mol %, about 9 mol %, about 18 mol %, or about 35 mol % to about
40 mol %, about 47 mol %, about 55 mol %, about 70 mol %, about 85
mol %, or about 97 mol %. The pressure of the C.sub.2-rich overhead
in line 161 can be about 400 kPa, about 500 kPa, about 600 kPa, or
about 700 kPa to about 3,500 kPa, about 3,800 kPa, about 4,500 kPa,
or about 4,800 kPa. The temperature of the C.sub.2-rich overhead in
line 161 can be about -83.degree. C., about -80.degree. C., about
-77.degree. C., about -75.degree. C., about -73.degree. C., about
-65.degree. C., about -60.degree. C., about -55.degree. C., about
-53.degree. C., about -50.degree. C., about -48.degree. C., about
-45.degree. C., about -43.degree. C., about -40.degree. C., about
-38.degree. C., about -35.degree. C., about -33.degree. C., about
-30.degree. C., about -27.degree. C., about -25.degree. C., or
about -23.degree. C. to about -20.degree. C., about -17.degree. C.,
about -15.degree. C., about -13.degree. C., about -10.degree. C.,
about -8.degree. C., about -5.degree. C., about -3.degree. C.,
about 0.degree. C., about 5.degree. C., about 10.degree. C., about
12.degree. C., about 15.degree. C., or about 17.degree. C.
[0039] The C.sub.2-lean bottoms in line 163 can include, but is not
limited to, propane, propylene, methylacetylene (propyne), and/or
propadiene. The propane concentration in the C.sub.2-lean bottoms
in line 163 can be about 5 mol %, about 10 mol %, about 20 mol %,
or about 40 mol % to about 50 mol %, about 60 mol %, about 80 mol
%, or about 95 mol %. The propylene concentration in the
C.sub.2-lean bottoms in line 163 can be about 5 mol %, about 10 mol
%, about 20 mol %, or about 40 mol % to about 50 mol %, about 60
mol %, about 80 mol %, or about 95 mol %. The methylacetylene
concentration in the C.sub.2-lean bottoms in line 163 can be about
0.1 mol %, about 0.3 mol %, about 0.5 mol %, or about 0.7 mol % to
about 1.5 mol %, about 1.7 mol %, about 2 mol %, or about 2.5 mol
%. The propadiene concentration in the C.sub.2-lean bottoms in line
163 can be about 1 mol %, about 1.5 mol %, about 2 mol %, or about
2.5 mol % to about 4 mol %, about 4.5 mol %, about 5 mol %, or
about 6 mol %.
[0040] The deethanizer 160 can include one or more systems,
devices, or any combination of systems and/or devices suitable for
providing the C.sub.2-rich overhead via line 161 and the
C.sub.2-lean bottoms via line 163. In some examples, the
deethanizer 160 can provide the C.sub.2-rich overhead via line 161
and the C.sub.2-lean bottoms via line 163. The deethanizer 160 can
include a vertical column having a length over diameter (L/D) ratio
greater than 1, greater than 5, or greater than 10. All or a
portion of the interior of the deethanizer can be filled with trays
and/or packing to increase the effective mass transfer area within
the deethanizer. All or a portion of the interior of the
deethanizer can be empty that is without trays or packing. One or
more condensers can be located internal or external to the
deethanizer. One or more reboilers can be located internal or
external to the deethanizer.
[0041] The C.sub.2-rich overhead via line 161 can be introduced to
the vapor-liquid separator ("C.sub.2 splitter") 175 to provide an
ethylene-rich overhead ("first product") via line 176 and an
ethane-rich bottoms ("second product") via line 178. The operating
pressure within the C.sub.2-splitter 175 can be about 360 kPa,
about 400 kPa, about 600 kPa, about 800 kPa, about 1,000 kPa, about
1,200 kPa, about 1,400 kPa, about 1,600 kPa, about 1,800 kPa, about
2,000 kPa, or about 2,200 kPa to about 2,500 kPa, about 2,700 kPa,
about 3,000 kPa, about 3,300 kPa, about 3,500 kPa, about 3,700 kPa,
or about 4,000 kPa. For example, the pressure within the
C.sub.2-splitter 175 can be about 360 kPa to about 4,000 kPa, about
500 kPa to about 3,500 kPa, about 900 kPa to about 3,000 kPa, or
about 1,300 kPa to about 2,600 kPa.
[0042] In one or more embodiments, the first product or ethylene
can be separated from the second hydrocarbon mixture at a pressure
of about 360 kPa, about 400 kPa, about 450 kPa, about 500 kPa,
about 550 kPa, about 600 kPa, about 700 kPa, about 750 kPa, about
800 kPa, about 850 kPa, about 900 kPa, about 950 kPa, about 1,000
kPa, about 1,050 kPa, about 1,100 kPa, about 1,150 kPa, about 1,200
kPa, about 1,250 kPa, about 1,300 kPa, about 1,350 kPa, about 1,400
kPa, about 1,450 kPa, or about 1,500 kPa to about 2,000 kPa, about
2,100 kPa, about 2,200 kPa, about 2,300 kPa, about 2,400 kPa, about
2,500 kPa, about 2,600 kPa, about 2,700 kPa, about 2,800 kPa, about
2,900 kPa, about 3,000 kPa, about 3,100 kPa, about 3,200 kPa, about
3,300 kPa, about 3,400 kPa, about 3,500 kPa, about 3,600 kPa, about
3,700 kPa, about 3,800 kPa, about 3,900 kPa, or about 4,000 kPa. In
one or more embodiments, the first product or ethylene can be
separated from the second hydrocarbon mixture at a pressure of at
least 360 kPa, at least 400 kPa, at least 450 kPa, at least 500
kPa, at least 550 kPa, at least 600 kPa, at least 700 kPa, at least
750 kPa, at least 800 kPa, at least 850 kPa, at least 900 kPa, at
least 950 kPa, at least 1,000 kPa, at least 1,050 kPa, at least
1,100 kPa, at least 1,150 kPa, at least 1,200 kPa, at least 1,250
kPa, at least 1,300 kPa, at least 1,350 kPa, at least 1,400 kPa, at
least 1,450 kPa, or at least 1,500 kPa, to less than 2,000 kPa,
less than 2,100 kPa, less than 2,200 kPa, less than 2,300 kPa, less
than 2,400 kPa, less than 2,500 kPa, less than 2,600 kPa, less than
2,700 kPa, less than 2,800 kPa, less than 2,900 kPa, less than
3,000 kPa, less than 3,100 kPa, less than 3,200 kPa, less than
3,300 kPa, less than 3,400 kPa, less than 3,500 kPa, less than
3,600 kPa, less than 3,700 kPa, less than 3,800 kPa, less than
3,900 kPa, or less than 4,000 kPa.
[0043] The operating temperature of the C.sub.2-splitter 175 can be
greater than the boiling point of propylene (e.g., about
-48.1.degree. C.). In one or more embodiments, the first product or
ethylene can be separated from the second hydrocarbon mixture at a
temperature of about -48.degree. C., about -47.degree. C., about
-46.degree. C., about -45.degree. C., about -44.degree. C., about
-43.degree. C., about -42.degree. C., about -41.degree. C., about
-40.degree. C., about -39.degree. C., about -38.degree. C., about
-37.degree. C., about -36.degree. C., about -35.degree. C., about
-34.degree. C., about -33.degree. C., about -32.degree. C., about
-31.degree. C., about -30.degree. C., about -29.degree. C., about
-28.degree. C., about -27.degree. C., about -26.degree. C., about
-25.degree. C., about -24.degree. C., about -23.degree. C., about
-22.degree. C., about -21.degree. C., about -20.degree. C., about
-19.degree. C., about -18.degree. C., about -17.degree. C., about
-16.degree. C., about -15.degree. C., about -14.degree. C., or
about -13.degree. C. to about -10.degree. C., about -7.degree. C.,
about -5.degree. C., about -3.degree. C., about 0.degree. C., about
3.degree. C., about 5.degree. C., about 7.degree. C., about
10.degree. C., about 12.degree. C., about 14.degree. C., or about
17.degree. C. In one or more embodiments, the first product or
ethylene can be separated from the second hydrocarbon mixture at a
temperature of greater than -48.degree. C., greater than
-45.degree. C., greater than -43.degree. C., greater than
-41.degree. C., greater than -38.degree. C., greater than
-35.degree. C., greater than -33.degree. C., greater than
-30.degree. C., greater than -27.degree. C., greater than
-25.degree. C., greater than -23.degree. C., greater than
-20.degree. C., greater than -17.degree. C., greater than
-15.degree. C., or greater than -13.degree. C. to less than
-10.degree. C., less than -7.degree. C., less than -5.degree. C.,
less than -3.degree. C., less than 0.degree. C., less than
3.degree. C., less than 5.degree. C., less than 7.degree. C., less
than 10.degree. C., less than 12.degree. C., less than 14.degree.
C., or less than 17.degree. C.
[0044] The ethylene concentration of the first product in line 176
can be greater than 85 mol %, greater than 87 mol %, greater than
90 mol %, greater than 92 mol %, greater than 93 mol %, greater
than 94 mol %, greater than 95 mol %, greater than 96 mol %,
greater than 97 mol %, greater than 98 mol %, greater than 98.5 mol
%, greater than 99 mol %, greater than 99.5 mol %, or greater than
99.9 mol %. The pressure of the first product in line 176 can be
about 400 kPa, about 500 kPa, about 600 kPa, or about 700 kPa to
about 2,500 kPa, about 2,700 kPa, about 3,300 kPa, or about 4,000
kPa. The temperature of the first product in line 176 can be about
-48.degree. C., about -45.degree. C., about -43.degree. C., about
-40.degree. C., about -38.degree. C., about -35.degree. C., about
-33.degree. C., about -30.degree. C., about -27.degree. C., about
-25.degree. C., about -23.degree. C., about -20.degree. C., about
-17.degree. C., about -15.degree. C., or about -13.degree. C. to
about -10.degree. C., about -7.degree. C., about -5.degree. C.,
about -3.degree. C., about 0.degree. C., about 3.degree. C., about
5.degree. C., about 7.degree. C., about 10.degree. C., about
13.degree. C., about 15.degree. C., or about 17.degree. C.
[0045] The ethane concentration in the second product in line 178
can be greater than 85 mol %, greater than 87 mol %, greater than
90 mol %, greater than 92 mol %, greater than 93 mol %, greater
than 94 mol %, greater than 95 mol %, greater than 96 mol %,
greater than 97 mol %, greater than 98 mol %, greater than 98.5 mol
%, greater than 99 mol %, greater than 99.5 mol %, or greater than
99.9 mol %. The pressure of the second product in line 178 can be
about 400 kPa, about 500 kPa, about 600 kPa, or about 700 kPa to
about 2,500 kPa, about 2,700 kPa, about 3,300 kPa, or about 4,000
kPa. The temperature of the second product in line 178 can be about
-48.degree. C., about -45.degree. C., about -43.degree. C., about
-40.degree. C., about -38.degree. C., about -35.degree. C., about
-33.degree. C., about -30.degree. C., about -27.degree. C., about
-25.degree. C., about -23.degree. C., about -20.degree. C., about
-17.degree. C., about -15.degree. C., or about -13.degree. C. to
about -10.degree. C., about -7.degree. C., about -5.degree. C.,
about -3.degree. C., about 0.degree. C., about 3.degree. C., about
5.degree. C., about 7.degree. C., about 10.degree. C., about
13.degree. C., about 15.degree. C., or about 17.degree. C.
[0046] The one or more C.sub.2-splitters 175 can include one or
more systems, devices, or any combination of systems and/or devices
suitable for providing an overhead containing ethylene and a
bottoms containing ethane. The C.sub.2-splitter 190 can be a
vertical column having a length over diameter (L/D) ratio greater
than 1, greater than 5, or greater than 10. All or a portion of the
interior of the C.sub.2-splitter 190 can be filled with trays
and/or packing to increase the effective mass transfer area within
the C.sub.2-splitter 190. All or a portion of the interior of the
C.sub.2-splitter 190 can be empty, that is without trays or
packing. One or more condensers can be located internal or external
to the C.sub.2-splitter 190. One or more reboilers can be located
internal or external to the C.sub.2-splitter 190.
[0047] In one or more embodiments, all or a portion of the second
product in line 178 can be recycled to the pyrolytic process used
to provide all or a portion of the hydrocarbon in line 102. For
example, about 5% or more, about 25% or more, about 50% or more,
about 75% or more, about 85% or more, about 90% or more, about 95%
or more, about 99% or more, or about 99.9% or more of the second
product in line 178 can be recycled to the pyrolytic process used
to provide all or a portion of the hydrocarbon in line 102.
[0048] In one or more embodiments, the C.sub.2-lean bottoms in line
163 can be introduced to the reactor system ("MAPD converter") 165
to provide a C.sub.2-lean bottoms via line 167 having a reduced
concentration of methylacetylene and/or propadiene. Hydrogen via
line 164 can be introduced to the MAPD converter 165. The
methylacetylene and/or the propadiene present in the C.sub.2-lean
bottoms introduced via line 163 to the MAPD converter 165 can be
converted to propylene. The hydrogen added via line 138 can be
about 50 mol % hydrogen or greater, about 75 mol % hydrogen or
greater, about 90 mol % hydrogen or greater, about 95 mol %
hydrogen or greater, about 99 mol % hydrogen or greater, or about
99.9 mol % hydrogen or greater. The hydrogen added via line 138 can
contain carbon monoxide and/or carbon dioxide.
[0049] In one or more embodiments, about 75%, about 80%, about 90%,
about 95%, about 99%, or about 99.9% of the methylacetylene and/or
propadiene present in the C.sub.2-lean bottoms in line 163 can be
converted to propylene in the MAPD converter 165. The
methylacetylene concentration in the hydrogenated mixture via line
167 can be about 1 mol % or less, about 0.5 mol %, about 0.1 mol %,
about 0.05 mol %, about 0.03 mol %, about 0.01 mol %, or less. The
propadiene concentration in the hydrogenated mixture via line 167
can be about 1 mol % or less, about 0.5 mol %, about 0.1 mol %,
about 0.05 mol %, about 0.03 mol %, about 0.01 mol %, or less.
[0050] The MAPD converter 165 can include one or more systems,
devices or combination of systems and/or devices suitable for
converting at least a portion of any methylacetylene and/or
propadiene present in the C.sub.2-lean bottoms in line 163 to
propylene. In one or more embodiments, the MAPD converter 165 can
contain one or more catalyst beds. In one or more embodiments, the
one or more catalyst beds can be fixed beds, fluidized beds,
ebullating beds, slurry beds, moving beds, bubbling beds, any other
suitable type of catalyst bed, or combinations thereof. In one or
more embodiments, the catalyst within the MAPD converter 165 can
include, but is not limited to, one or more palladium-based based
catalysts, such as available catalyst vendors such as Axens, CRI
Catalyst Company, or Sud-Chemie, or any mixture thereof.
[0051] The C.sub.2-lean bottoms via line 167 having a reduced
concentration of methylacetylene and/or propadiene can be
introduced to the vapor-liquid separator ("C.sub.3 splitter") 170
to provide a propylene-rich overhead ("third product") via line 172
and a propane-rich bottoms ("fourth product") via line 174.
Although not shown, in one or more embodiments, all or a portion of
the fourth product in line 174 can be recycled to the pyrolytic
process used to provide all or a portion of the hydrocarbon in line
102. In one or more embodiments, about 5% or more, about 25% or
more, about 50% or more, about 75% or more, about 85% or more,
about 90% or more, about 95% or more, about 99% or more, or about
99.9% or more of the fourth product in line 174 can be recycled to
the pyrolytic process used to provide all or a portion of the
hydrocarbon in line 102.
[0052] FIG. 2 depicts the illustrative chilling system 200 shown in
FIG. 1, according to one or more embodiments. The chilling system
200 can include the first cooler 140 and the second cooler 145, as
discussed and described above with reference to FIG. 1. In one or
more embodiments, the first cooler 140 can include one or more heat
exchangers (four are shown 205, 210, 215, 220) and one or more
vapor/liquid separators "knock-out drums" 225. In one or more
embodiments, the second cooler 145 can include one or more heat
exchangers 230 (nine are shown), one or more knock-out drums (two
are shown 235, 240), and one or more multi-pass exchanger known
typical in the industry as a coldbox 250. The heat exchangers 205,
210, 215, and 220 can be shell-and-tube heat exchangers and the
heat exchanges 230 can be core-type heat exchangers. The multi-pass
heat exchanger or the coldbox 250 can be or include one or more
heat exchangers configured to cool and/or hear one or more streams
using brazed aluminum heat transfer cores at least partially
contained within an insulated box. For example, as shown the cold
box 250 can include three heat exchangers 230.
[0053] The hydrogenated mixture via line 136 can be serially
introduced to the heat exchangers 205, 210, 215, and 220 to provide
an at least partially condensed hydrogenated mixture via line 222.
Although not shown, the hydrogenated mixture via line 136 can be
introduced in parallel, in series/parallel, and/or in
parallel/series to two or more heat exchangers to provide the at
least partially condensed hydrogenated mixture via line 222.
[0054] The at least partially condensed hydrogenated mixture via
line 222 can be introduced to the knock-out drum 225 to provide the
cooled hydrogenated mixture via line 142 and the gaseous
hydrogenated mixture via line 144. The gaseous hydrogenated mixture
via line 144 can be introduced to one or more of the heat
exchangers 230 (one as shown) and the knock-out drum 235 to provide
the condensed hydrogenated mixture via line 147 and a tail gas via
line 237. The tail gas via line 237 can be introduced to one or
more of the heat exchangers 230 (one as shown) and the knock-out
drum 240 to provide a hydrogen-rich tail gas via line 241 and a
hydrogen-lean tail gas via line 243.
[0055] In one or more embodiments, the hydrogen-rich tail gas via
line 241 can be introduced through one or more heat exchangers 230
(two as shown) to provide a heated hydrogen-rich tail gas via line
245. In one or more embodiments, the hydrogen-lean tail gas via
line 243 can be introduced through one or more heat exchangers 230
(two as shown) to provide a heated hydrogen-lean tail gas via line
247. The hydrogen-rich tail gas via line 245 and the hydrogen-lean
tail gas via line 247 can be introduced to the coldbox 250 to
provide the hydrogen-rich tail gas via line 149 and the
hydrogen-lean tail gas via line 151, as shown in FIG. 1.
[0056] In one or more embodiments, propylene via line 251 can be
introduced to one or more compressors 253 to provide a compressed
propylene via line 255. In one or more embodiments, the pressure of
the propylene in line 251 can be increased by about 1,500 kPa or
greater, about 2,000 kPa or greater, about 2,500 kPa or greater, or
about 3,000 kPa or greater by passage through the one or more
compressors 253. The compressed propylene in line 255 can be at a
temperature of about 40.degree. C., about 45.degree. C., about
50.degree. C., or about 55.degree. C. to about 80.degree. C., about
85.degree. C., about 90.degree. C., or about 95.degree. C. Although
not shown, in one or more embodiments, the compressed propylene
from the compressor 253 can be cooled via indirect heat exchange to
provide the compressed propylene via line 255.
[0057] The compressor 253 can include one or more systems, devices,
or combination of systems and/or devices suitable for compressing a
fluid at a first pressure to provide a fluid at a second pressure,
where the second pressure is greater than the first pressure. The
compressor 253 can include one or more stages, two or more separate
and independent compressors, or a combination thereof. The
compressor 253 can include one or more intercoolers between any two
or more compressors and/or compressor stages. Shaft power can be
supplied to the one or more compressors 253 via one or more
electric motors, steam turbines, gas turbines, or any combination
thereof.
[0058] In one or more embodiments, propylene via line 255 can be
introduced to the coldbox 250, where heat can be indirectly
transferred from the propylene to the hydrogen-rich tail gas and/or
the hydrogen-lean tail gas introduced via lines 245 and 247,
respectively. The cooled propylene via line 257 can be recovered
from the coldbox 250.
[0059] In one or more embodiments, at least a portion of the
hydrogen-lean tail gas via line 151 can be recycled to the
compressor 105. For example, at least a portion of the
hydrogen-lean tail gas via line 151 can be recycled to the second
stage 108 of the compressor 105. In one or more embodiments, the
hydrogen-rich tail gas via line 149 can be recovered from the
chilling system 200 as a product. In one or more embodiments, the
hydrogen-rich tail gas via line 151 can be introduced to the one or
more reactor systems 135 and/or 165 via lines 138 and 164,
respectively.
[0060] Embodiments of the present disclosure further relate to any
one or more of the following paragraphs:
[0061] 1. A method for separating one or more olefins comprising:
separating at least a portion of one or more C.sub.3 and heavier
hydrocarbons from a hydrocarbon comprising C.sub.1 to C.sub.20
hydrocarbons to provide a first hydrocarbon mixture comprising
methane, ethane, ethylene, and acetylene; hydrogenating at least a
portion of the first hydrocarbon mixture to convert at least a
portion of the acetylene to ethane and ethylene; separating at
least a portion of the methane from the hydrogenated mixture to
provide a second hydrocarbon mixture comprising ethane and
ethylene; and separating at least a portion of the ethylene from
the second hydrocarbon mixture to provide a first product
comprising at least 95 mol % ethylene and a second product
comprising at least 95 mol % ethane, wherein the ethylene is
separated from the second hydrocarbon mixture at a pressure of
about 360 kPa to about 4,000 kPa.
[0062] 2. The method according to paragraph 1, further comprising
transferring at least a portion of the second product to a
pyrolysis furnace.
[0063] 3. The method according to paragraph 1 or 2, wherein the one
or more C.sub.3 and heavier hydrocarbons are separated from the
hydrocarbon comprising C.sub.1 to C.sub.20 hydrocarbons at a
pressure of about 400 kPa to about 3,000 kPa.
[0064] 4. The method according to any one of paragraphs 1 to 3,
wherein the methane is separated from the hydrogenated mixture at a
pressure of about 600 kPa to about 4,200 kPa, and the ethylene is
separated from the second hydrocarbon mixture at a pressure of
about 500 kPa to about 2,500 kPa.
[0065] The method according to any one of paragraphs 1 to 4,
wherein at least a portion of the hydrocarbon comprising C.sub.1 to
C.sub.20 hydrocarbons is produced by cracking a heavy hydrocarbon
containing C.sub.4+ hydrocarbons in a fluid catalytic cracker, a
pyrolytic process, or combination thereof.
[0066] 6. The method according to any one of paragraphs 1 to 5,
wherein the one or more C.sub.3 and heavier hydrocarbons are
separated from the hydrocarbon comprising C.sub.1 to C.sub.20
hydrocarbons at a pressure of about 800 kPa to about 2,000 kPa, the
methane is separated from the hydrogenated mixture at a pressure of
about 900 kPa to about 3,500 kPa, and the ethylene is separated
from the second hydrocarbon mixture at a pressure of about 500 kPa
to about 2,500 kPa.
[0067] 7. The method according to any one of paragraphs 1 to 6,
wherein the first hydrocarbon mixture is hydrogenated in the
presence of a catalyst.
[0068] 8. The method according to any one of paragraphs 1 to 7,
wherein the methane concentration in the hydrocarbon comprising
C.sub.1 to C.sub.20 hydrocarbons is less than 12 mol %.
[0069] 9. A method for separating one or more olefins comprising:
compressing a gas comprising one or more C.sub.1-C.sub.20
hydrocarbons, water, one or more acid gases, and hydrogen;
scrubbing at least a portion of the compressed fluid to remove at
least a portion of the one or more acid gases; separating at least
a portion of the water from the compressed fluid to provide a
dehydrated fluid containing less than 0.5 mol % water, wherein the
dehydrated fluid comprises the one or more C.sub.1-C.sub.20
hydrocarbons; separating at least a portion of one or more C.sub.4
and heavier hydrocarbons from the dehydrated fluid to provide a
hydrocarbon comprising one or more C.sub.1-C.sub.3 hydrocarbons;
separating at least a portion of one or more C.sub.3 hydrocarbons
from the hydrocarbon comprising one or more C.sub.1-C.sub.3
hydrocarbons to provide a first hydrocarbon mixture comprising
ethane, ethylene, acetylene, and methane; hydrogenating at least a
portion of the first hydrocarbon mixture to convert at least a
portion of the acetylene to ethane and ethylene; separating at
least a portion of the methane from the hydrogenated mixture to
provide a second hydrocarbon mixture comprising ethane and
ethylene; and separating at least a portion of the ethylene from
the second hydrocarbon mixture to provide a first product
comprising at least 95 mol % ethylene and a second product
comprising at least 95 mol % ethane, wherein the ethylene is
separated from the second hydrocarbon mixture at a pressure of
about 360 kPa to about 4,000 kPa.
[0070] 10. The method according to paragraph 9, further comprising
transferring all or a portion of the second product to a pyrolysis
furnace.
[0071] 11. The method according to paragraph 9 or 10, wherein the
gas has a methane concentration of less than 15 mol %.
[0072] 12. The method according to any one of paragraphs 9 to 11,
wherein the gas has a hydrogen concentration of less than 15 mol
%.
[0073] 13. The method according to any one of paragraphs 9 to 12,
wherein the one or more C.sub.4 and heavier hydrocarbons are
separated from the dehydrated fluid at a pressure of about 500 kPa
to about 3,500 kPa.
[0074] 14. The method according to any one of paragraphs 9 to 13,
wherein the one or more C.sub.3 hydrocarbons are separated from the
hydrocarbon comprising one or more C.sub.1-C.sub.3 hydrocarbons at
a pressure of about 400 kPa to about 3,000 kPa.
[0075] 15. The method according to any one of paragraphs 9 to 14,
wherein at least a portion of the hydrocarbon comprising one or
more C.sub.1-C.sub.3 hydrocarbons is produced by cracking a heavy
hydrocarbon containing C.sub.4+ hydrocarbons in a fluid catalytic
cracker, a pyrolytic process, or a combination thereof.
[0076] 16. The method according to any one of paragraphs 9 to 15,
wherein the ethylene is separated from the second hydrocarbon
mixture at a pressure of about 500 kPa to about 2,500 kPa.
[0077] 17. The method according to any one of paragraphs 9 to 16,
wherein the one or more C.sub.3 and heavier hydrocarbons are
separated from the hydrocarbon comprising C.sub.1 to C.sub.20
hydrocarbons at a pressure of about 800 kPa to about 2,000 kPa, the
methane is separated from the hydrogenated mixture at a pressure of
about 900 kPa to about 3,500 kPa, and the ethylene is separated
from the second hydrocarbon mixture at a pressure of about 500 kPa
to about 2,500 kPa.
[0078] 18. A system for producing one or more olefins comprising:
one or more first separators for separating at least a portion of
one or more C.sub.3 and heavier hydrocarbons from a hydrocarbon
comprising C.sub.1 to C.sub.20 hydrocarbons to provide a first
hydrocarbon mixture comprising ethane, ethylene, and acetylene; one
or more hydrogenators for hydrogenating at least a portion of the
first hydrocarbon mixture to convert at least a portion of the
acetylene to ethane and ethylene; one or more second separators for
separating at least a portion of the methane from the hydrogenated
mixture to provide a second hydrocarbon mixture comprising ethane
and ethylene; and one or more third separators for separating at
least a portion of the ethylene from the second hydrocarbon mixture
at a pressure of about 360 kPa to about 4,000 kPa to provide a
first product comprising at least 95 mol % ethylene and a second
product comprising at least 95 mol % ethane.
[0079] 19. The system according to paragraph 18, further comprising
a recycle line for transferring at least a portion of the second
product to a pyrolysis furnace.
[0080] 20. The system according to paragraph 18 or 19, wherein the
methane concentration of the hydrocarbon comprising C.sub.1 to
C.sub.20 hydrocarbons is less than 12 mol %.
[0081] 21. A system for producing one or more olefins comprising:
means for separating at least a portion of one or more C.sub.3 and
heavier hydrocarbons from a hydrocarbon comprising C.sub.1 to
C.sub.20 hydrocarbons to provide a first hydrocarbon mixture
comprising ethane, ethylene, and acetylene; means for hydrogenating
at least a portion of the first hydrocarbon mixture to convert at
least a portion of the acetylene to ethane and ethylene; means for
separating at least a portion of the methane from the hydrogenated
mixture to provide a second hydrocarbon mixture comprising ethane
and ethylene; and means for separating at least a portion of the
ethylene from the second hydrocarbon mixture at a pressure of about
360 kPa to about 4,000 kPa to provide a first product comprising at
least 95% mol ethylene and a second product comprising at least 95%
mol ethane.
[0082] 22. The system according to paragraph 21, further comprising
a means for transferring all or a portion of the second product to
a pyrolysis furnace.
[0083] 23. The system according to paragraph 22, wherein the
methane concentration of the hydrocarbon comprising C.sub.1 to
C.sub.20 hydrocarbons is less than 12% mol.
[0084] 24. The method or system according to any one of paragraphs
1 to 23, wherein the ethylene is separated from the second
hydrocarbon mixture at a pressure of about 400 kPa to about 4,000
kPa.
[0085] 25. The method or system according to any one of paragraphs
1 to 24, wherein the ethylene is separated from the second
hydrocarbon mixture at a pressure of about 600 kPa to about 4,000
kPa.
[0086] 26. The method or system according to any one of paragraphs
1 to 25, wherein the ethylene is separated from the second
hydrocarbon mixture at a pressure of about 800 kPa to about 4,000
kPa.
[0087] 27. The method or system according to any one of paragraphs
1 to 26, wherein the ethylene is separated from the second
hydrocarbon mixture at a pressure of about 1,000 kPa to about 4,000
kPa.
[0088] The method or system according to any one of paragraphs 1 to
27, wherein the ethylene is separated from the second hydrocarbon
mixture at a pressure of about 1,400 kPa to about 4,000 kPa.
[0089] 29. The method or system according to any one of paragraphs
1 to 28, wherein the ethylene is separated from the second
hydrocarbon mixture at a pressure of about 1,600 kPa to about 4,000
kPa.
[0090] 30. The method or system according to any one of paragraphs
1 to 29, wherein the ethylene is separated from the second
hydrocarbon mixture at a pressure of at least 400 kPa and less than
4,000 kPa.
[0091] 31. The method or system according to any one of paragraphs
1 to 30, wherein the ethylene is separated from the second
hydrocarbon mixture at a pressure of at least 600 kPa and less than
4,000 kPa.
[0092] 32. The method or system according to any one of paragraphs
1 to 31, wherein the ethylene is separated from the second
hydrocarbon mixture at a pressure of at least 800 kPa and less than
4,000 kPa.
[0093] 33. The method or system according to any one of paragraphs
1 to 32, wherein the ethylene is separated from the second
hydrocarbon mixture at a pressure of at least 1,000 kPa and less
than 4,000 kPa.
[0094] 34. The method or system according to any one of paragraphs
1 to 33, wherein the ethylene is separated from the second
hydrocarbon mixture at a pressure of at least 1,400 kPa and less
than 4,000 kPa.
[0095] 35. The method or system according to any one of paragraphs
1 to 34, wherein the ethylene is separated from the second
hydrocarbon mixture at a pressure of at least 1,600 kPa and less
than 4,000 kPa.
[0096] Certain embodiments and features have been described using a
set of numerical upper limits and a set of numerical lower limits.
It should be appreciated that ranges including the combination of
any two values, e.g., the combination of any lower value with any
upper value, the combination of any two lower values, and/or the
combination of any two upper values are contemplated unless
otherwise indicated. Certain lower limits, upper limits and ranges
appear in one or more claims below. All numerical values are
"about" or "approximately" the indicated value, and take into
account experimental error and variations that would be expected by
a person having ordinary skill in the art.
[0097] Various terms have been defined above. To the extent a term
used in a claim is not defined above, it should be given the
broadest definition persons in the pertinent art have given that
term as reflected in at least one printed publication or issued
patent. Furthermore, all patents, test procedures, and other
documents cited in this application are fully incorporated by
reference to the extent such disclosure is not inconsistent with
this application and for all jurisdictions in which such
incorporation is permitted.
[0098] While the foregoing is directed to embodiments, other and
further embodiments of the invention can be devised without
departing from the basic scope thereof, and the scope thereof is
determined by the claims that follow.
* * * * *